Journal of Comparative Psychology

Article	Citations
Beyond the information (not) given: Associative mechanisms versus representations of uncertainty in extinction in laboratory rats (Rattus norvegicus).	15
Form over function: Striped skunks (mephitis mephitis) learn arbitrary visual patterns to solve the slat-pulling task.	14
Pigeons’ (Columba livia) intertemporal choice in binary-choice and patch-leaving contexts.	13
Supplemental Material for Eyes or Nose: Domestic Dogs (Canis familiaris) Prefer Vision Over Olfaction When Searching for Food	11
Supplemental Material for Influence of Group Size on Shelter Choice in Blaptica dubia Cockroaches	10
Supplemental Material for Is Economic Risk Proneness in Young Children (Homo sapiens) Driven by Exploratory Behavior? A Comparison With Capuchin Monkeys (Sapajus apella)	10
Supplemental Material for Cognitive Flexibility and Aging in Coyotes (Canis latrans)	10
Supplemental Material for A Modified Version of the Dimensional Change Card Sort Task Tests Cognitive Flexibility in Children (Homo sapiens) and Cotton-Top Tamarins (Saguinus oedipus)	9
Supplemental Material for Sensitivity to Immature Skill Deficits. Food Sharing Experiments in Squirrel Monkeys (Saimiri boliviensis) and Common Marmosets (Callithrix jacchus)	8
Acknowledgments	8
Supplemental Material for Gaze in Cats (Felis catus) and Dogs (Canis lupus familiaris)	8
Supplemental Material for Variation in Neophilia in Seven Primate Species	7
African striped mice (Rhabdomys) mind the neighbors.	5
Effects of ethanol ingestion on aversive conditioning in honey bees (Apis mellifera L.).	5
Dogs (Canis familiaris) prioritize independent exploration over looking back.	5
Don't let the pigeon chair the search committee: Pigeons (Columba livia) match humans’ (Homo sapiens) suboptimal approach to the secretary problem.	5
Supplemental Material for Testing Three Primate Species’ Attentional Biases Toward Preferred and Unpreferred Foods: Seeing Red or High Valued Food?	5
Individual variation in Black-capped chickadee (Poecile atricapillus) foraging behavior in response to a predator model.	4
Tolerance of muzzle contact underpins the acquisition of foraging information in vervet monkeys (Chlorocebus pygerythrus).	4
Testing three primate species’ attentional biases toward preferred and unpreferred foods: Seeing red or high valued food?	4
Cyclical variations in acoustic features within the song sessions of humpback whales (Megaptera novaeangliae).	4
Cognitive flexibility and aging in coyotes (Canis latrans).	4
What enables “distraction” to reduce delay discounting for pigeons (Columba livia).	4
Behavioral and hormonal changes following social instability in young rhesus macaques (Macaca mulatta).	4
Testing the role of macaque social tolerance in ability to follow human eye gaze.	4

Cross-modal perception of puppies and adult conspecifics in dogs (Canis familiaris).	4
Sexual dimorphism in classical conditioning? Sex differences in neophobia, latent inhibition, generalization, and extinction for rats (Rattus norvegicus) in a conditioned taste aversion preparation ir	4
How environmental unpredictability and harshness affect chimpanzees (Pan troglodytes) in risk-choice and temporal discounting tasks.	4
Still face in pet dogs (Canis familiaris).	4
Spatial frequency and global–local visual processing in capuchin monkeys (Sapajus spp.) and humans (Homo sapiens).	4
Same-different conceptualization in dogs (Canis familiaris).	4
Sensitivity to line-of-sight in tolerant versus despotic macaques (Macaca sylvanus and Macaca mulatta).	4
Stone affordances as potential for action expression in object play in long-tailed macaques (Macaca fascicularis).	4
Monkeys (Macaca mulatta) rank lists using multiple cognitive mechanisms simultaneously.	3
Supplemental Material for Mother–Infant Relationships and Infant Independence in Wild Geoffroy’s Spider Monkeys (Ateles geoffroyi)	3
Supplemental Material for Is Inferential Reasoning a Distinctly Human Cognitive Feature? Testing Reasoning in Cotton-Top Tamarins (Saguinus oedipus)	3
Supplemental Material for Investigation of Mirror-Self Recognition in Ravens (Corvus corax)	3
Sensitivity to immature skill deficits. Food sharing experiments in squirrel monkeys (Saimiri boliviensis) and common marmosets (Callithrix jacchus).	3
Primate socio-ecology shapes the evolution of distinctive facial repertoires.	3
Chimpanzees (Pan troglodytes) with better task-based delay of gratification skills are rated as less impulsive, more agreeable, and smarter.	3
Supplemental Material for The Dynamics of Chunking in Humans (Homo sapiens) and Guinea Baboons (Papio papio)	3
Pitch affects human (Homo sapiens) perception of emotional arousal from diverse animal calls.	3
Assessing the perception of face pareidolia in children (Homo sapiens), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Sapajus apella).	3
Supplemental Material for Dominance in Human (Homo sapiens) Personality Space and in Hominoid Phylogeny	3
Supplemental Material for Assessing Cats’ (Felis catus) Sensitivity to Human Pointing Gestures	3
Within the sound of trouble: Do humans use pitch to correctly assess emotional arousal across species?	2
Mother–infant relationships and infant independence in wild Geoffroy’s spider monkeys (Ateles geoffroyi).	2
How do communicative cues shape the way that dogs (Canis familiaris) encode objects?	2
Learning simple and compound stimuli in a social lizard (Egernia stokesii).	2
Conflict interference in an insect.	2
Acknowledgment	2
Supplemental Material for Implementation of Automated Cognitive Testing Systems for Socially Housed Rhesus (Macaca mulatta) and Squirrel (Saimiri spp.) Monkeys: Age Differences in Learning	2
Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) chase prey around obstacles in virtual environments.	2
Iberian Lynx (Lynx pardinus) personality: A rating assessment with ex Situ Conservation Program sample.	2
Simplicity and complexity in human and nonhuman communication.	2
Positive intonation increases the perceived value of smaller rewards in a quantity discrimination task with dogs (Canis familiaris).	2
Supplemental Material for Evaluation of Decision-Making Behavior Under Uncertainty in Capuchin Monkeys (Sapajus apella) and Humans (Homo sapiens) Using a Modified Balloon Analogue Risk Task	2
Supplemental Material for Hearing “Number”?: Relative Quantity Judgments Through the Echolocation by Bottlenose Dolphins (Tursiops truncatus)	2
Clark’s nutcrackers (Nucifraga columbiana) use a visual barrier for cache protection.	2
Personality structure in bottlenose dolphins (Tursiops truncatus).	2
Sound order discrimination in two species of birds–Taeniopygia guttata and Melopsittacus undulatus.	1
Adaptable navigation in bull ants (Myrmecia midas).	1
Drawing in nonhuman primates: What we know and what remains to be investigated.	1
Environmental correlates of exploratory behavior and anxiety in three African striped mouse (Rhabdomys) taxa occurring in different habitats and contexts.	1
Why do distractions sometimes aid self-control? Pigeons (Columba livia) highlight possible mechanisms underlying the distraction effect.	1
Have we met? New insights into the role of head and body cues in the visual recognition of conspecifics in gray parrots (Psittacus erithacus).	1
Gaze in cats (Felis catus) and dogs (Canis lupus familiaris).	1
Primate origins of corepresentation and cooperative flexibility: A comparative study with common marmosets (Callithrix jacchus), brown capuchins (Sapajus apella), and Tonkean macaques (Macaca tonkeana	1
Multiple assessments of personality and problem-solving performance in captive Asian elephants (Elephas maximus) and African savanna elephants (Loxodonta africana).	1
Recognition of visual kinship signals in chimpanzees (Pan troglodytes) by humans (Homo sapiens).	1
The role of head and body cues in visual individual recognition in grey parrots (Psittacus erithacus).	1
Supplemental Material for Cross-modal Perception of Puppies and Adult Conspecifics in Dogs (Canis familiaris)	1
Physiological constraints and cognitive chunking: Sequence organization in the songs of zebra finches (Taeniopygia guttata).	1
What makes the ephemeral reward task so difficult?	1
Are you as fooled as I am? Visual illusions in human (Homo) and nonhuman (Sapajus, Gorilla, Pan, Pongo) primate species.	1

A reflection on noncognitive factors affecting spatial cognitive testing: Examples from nonmodel species.	1
A study of executive function in grey parrots (Psittacus erithacus): Experience can affect delay of gratification.	1
Humans’ (Homo sapiens), capuchin monkeys’ (Sapajus [Cebus] apella), and rhesus macaques’ (Macaca mulatta) size judgments shift when stimuli change in frequency.	1
Supplemental Material for The Effect of Delta-9 Tetrahydrocannabinol and Methamphetamine on Sustained Attention in the Jumping Spider (Trite planiceps)	1
Impulsivity as a trait in domestic dogs (Canis familiaris): A systematic review and meta-analysis.	1
Evidence of motor intentions in plants: A kinematical study.	0
Supplemental Material for Are Chimpanzees Futurists? Effects of Motion Lines and Motion Blur on the Judgments of Global Motion Direction in Chimpanzees (Pan troglodytes)	0
Melodic and harmonic chromatic interval processing by pigeons (Columba livia).	0
Supplemental Material for Cyclical Variations in Acoustic Features Within the Song Sessions of Humpback Whales (Megaptera novaeangliae)	0
Supplemental Material for Chimpanzees (Pan troglodytes) Exhibit Gaze Bias for Snakes Upon Hearing Alarm Calls	0
Supplemental Material for Impulsivity as a Trait in Domestic Dogs (Canis familiaris): A Systematic Review and Meta-Analysis	0
Egg burial in the ringneck dove (Streptopelia risoria): A potential laboratory model system for egg-rejection research?	0
Expanding the landscape of opportunity: Professional societies support early-career researchers through community programming and peer coaching.	0
Acknowledgment of Ad Hoc Reviewers	0
Inhibitory control and cue relevance modulate chimpanzees’ (Pan troglodytes) performance in a spatial foraging task.	0
Responses to prey chemical cues in wild-caught, adult gopher snakes (Pituophis catenifer).	0
The journey in comparative psychology matters more than the destination.	0
Is inferential reasoning a distinctly human cognitive feature? Testing reasoning in cotton-top tamarins (Saguinus oedipus).	0
Individual recognition of monkey (Macaca fuscata) and human (Homo sapiens) images in primatologists.	0
Decoding the dilemma: Exploring the rules and cues of egg rejection in the American robin (Turdus migratorius) through conjoint experimentation.	0
Supplemental Material for A Study of Executive Function in Grey Parrots (Psittacus erithacus): Experience Can Affect Delay of Gratification	0
Supplemental Material for The Role of Head and Body Cues in Visual Individual Recognition in Grey Parrots (Psittacus erithacus)	0
Fins, feathers, fingers, and finding an explanation for the puzzle of ephemeral rewards.	0
End the search quickly: Pigeons (Columba livia) and humans (Homo sapiens) share the same bias.	0
Clark’s nutcrackers (Nucifraga columbiana) modify caching behavior when observed.	0
Supplemental Material for Consistent Second-Order Motor Planning by Cotton-Top Tamarins (Saguinus oedipus): Evidence From a Dowel Task	0
Supplemental Material for Effect of Resource-Associated Signals on Producer Responses: Insights From Golden Fish (Carassius auratus) and an Agent-Based Model	0
Variation in neophilia in seven primate species.	0
Supplemental Material for Using Isochrony, but Not Meter, to Discriminate Rhythmic Sequences in Rats (Rattus norvegicus)	0
Supplemental Material for Reach-to-Grasp Kinematic Signatures in Colombian Spider Monkeys (Ateles fusciceps rufiventris)	0
Supplemental Material for The Roles of Social Information, Asocial Information, and Initial Bias in Nest-Building Decisions	0
Responses of wild skuas (Catharacta antarctica ssp. lonnbergi) to human cues in cooperative and competitive social contexts.	0
Supplemental Material for The Effects of Goal–Landmark Distance on Overshadowing: A Replication in Humans (Homo sapiens) of Goodyear and Kamil (2004)	0
Chimpanzees (Pan troglodytes) exhibit gaze bias for snakes upon hearing alarm calls.	0
Supplemental Material for No Evidence of Attentional Bias Toward Threatening Conspecific and Allospecific Faces in Capuchin Monkeys (Sapajus [Cebus] apella) Using a Dot-Probe Task	0
One smell, two smells, intermixed, combined, or queued smells: What training procedure promotes the best generalization of odor detection by dogs?	0
How comparative was (is) the Journal of Comparative Psychology? A reptilian perspective.	0
Studying animal innovation at the individual level: A ratings-based assessment in capuchin monkeys (Sapajus [Cebus] sp.).	0
Supplemental Material for Search Asymmetries for Threatening Faces in Chimpanzees (Pan troglodytes)	0
Investigation of mirror-self recognition in ravens (Corvus corax).	0
I am as fooled as you are, say some primates … but only sometimes.	0
Visual discrimination of size and perception of the Delboeuf illusion in the domestic cat (Felis silvestris catus): A developmental disjunction?	0
No evidence of attentional bias toward threatening conspecific and allospecific faces in capuchin monkeys (Sapajus [Cebus] apella) using a dot-probe task.	0
Great apes (Pan troglodytes, Pan paniscus, Pongo abelii) exploit better the information of failure than capuchin monkeys (Sapajus spp.) when selecting tools to solve the same foraging problem.	0
Convergence between G and g in three monkey species (Sapajus spp, Ateles geoffroyi, and Macaca fascicularis).	0
Differences in paradoxical choice between pigeons (Columba livia) and rats (Rattus norvegicus): The problem of cue trackability.	0
Individual differences guide mate choice in the fighting fish (Betta splendens).	0
On parrots, delay of gratification, executive function, and how sometimes we do the best we can.	0
Zing-Yang Kuo and “Giving up instincts in psychology”, 100 years later.	0
The effect of delta-9 tetrahydrocannabinol and methamphetamine on sustained attention in the jumping spider (Trite planiceps).	0
Supplemental Material for Chimpanzees (Pan troglodytes) and Bonobos (Pan paniscus) Chase Prey Around Obstacles in Virtual Environments	0
Some phenomena of the cap-pushing response in honey bees (Apis mellifera spp.).	0
Together again but no need to play: Dissociating effects of isolation and separation on social interaction in female rats (Rattus norvegicus).	0
Supplemental Material for Primate Origins of Corepresentation and Cooperative Flexibility: A Comparative Study With Common Marmosets (Callithrix jacchus), Brown Capuchins (Sapajus apella), and Tonkean	0
Supplemental Material for Same-Different Conceptualization in Dogs (Canis familiaris)	0
Guatemalan beaded lizards (Helodermatidae: Heloderma charlesbogerti) navigate and follow a scent trail in maze tasks.	0
Chimpanzees’ (Pan troglodytes) internal arousal remains elevated if they cannot themselves help a conspecific.	0
Supplemental Material for Evidence of Motor Intentions in Plants: A Kinematical Study	0
Supplemental Material for No Same–Different Concept or Entropy Stimulus Control: Multiple-Item Array Task Performance in Budgerigars (Melopsittacus undulatus) and Pigeons (Columba livia)	0
Doing reliable research in comparative psychology: Challenges and proposals for improvement.	0
The effects of positive and negative experiences on subsequent behavior and cognitive performance in capuchin monkeys (Sapajus [Cebus] apella).	0
Supplemental Material for Detouring While Foraging Up a Tree: What Bull Ants (Myrmecia midas) Learn and Their Reactions to Novel Sensory Cues	0
Supplemental Material for Exploring Personality Structure and Similarity in Coppery Titi Monkeys (Plecturocebus cupreus)	0
Contrafreeloading in umbrella cockatoos (Cacatua alba): Further evaluation of the play hypothesis.	0
Children (Homo sapiens), but not rhesus monkeys (Macaca mulatta), perceive the one-is-more illusion.	0
Influence of group size on shelter choice in Blaptica dubia cockroaches.	0
Exclusion by donkey’s ears: Donkeys (Equus asinus) use acoustic information to find hidden food in a two-way object-choice task.	0
The effects of goal–landmark distance on overshadowing: A replication in humans (Homo sapiens) of Goodyear and Kamil (2004).	0
Supplemental Material for Physiological Constraints and Cognitive Chunking: Sequence Organization in the Songs of Zebra Finches (Taeniopygia guttata)	0
Supplemental Material for Sound Order Discrimination in Two Species of Birds–Taeniopygia guttata and Melopsittacus undulatus	0
Serial pattern learning: Pigeons (Columba livia) prefer an improving schedule over an initially easier fixed ratio schedule.	0
The “avoid the empty cup” hypothesis does not explain great apes’ (Gorilla gorilla, Pan paniscus, Pan troglodytes, Pongo abelii) responses in two three-cup one-item inference by exclusion tasks.	0
Supplemental Material for Inhibitory Control and Cue Relevance Modulate Chimpanzees’ (Pan troglodytes) Performance in a Spatial Foraging Task	0
Supplemental Material for Delayed Gratification: A Grey Parrot (Psittacus erithacus) Will Wait for More Tokens	0
The roles of social information, asocial information, and initial bias in nest-building decisions.	0
What is it like to hear quantities? Testing dolphins on classic number estimation using a sonar setup.	0
Supplemental Material for Contrafreeloading in Umbrella Cockatoos (Cacatua alba): Further Evaluation of the Play Hypothesis	0
Supplemental Material for Positive Intonation Increases the Perceived Value of Smaller Rewards in a Quantity Discrimination Task With Dogs (Canis familiaris)	0
Selenophobia (moonlight avoidance) in nocturnal rodents: A primer.	0
Supplemental Material for Do Standard Behavioral Assays Predict Foraging Behavior of Individual Black-Capped Chickadees (Poecile atricapillus) in Response to a Predator Model or Calls?	0

Anthropomorphism as a contributor to the success of human (Homo sapiens) tool use.	0
Initial evidence for eliciting contrafreeloading in grey parrots (Psittacus erithacus) via the opportunity for playful foraging.	0
Eyes or nose: Domestic dogs (Canis familiaris) prefer vision over olfaction when searching for food.	0
How tufted capuchin monkeys (Sapajus spp.) and humans (Homo sapiens) handle a jointed tool.	0
The coding of object thickness in plants: When roots matter.	0
Supplemental Material for Sensitivity to Line-of-Sight in Tolerant Versus Despotic Macaques (Macaca sylvanus and Macaca mulatta)	0
Consistent second-order motor planning by cotton-top tamarins (Saguinus oedipus): Evidence from a dowel task.	0
Implementation of automated cognitive testing systems for socially housed rhesus (Macaca mulatta) and squirrel (Saimiri spp.) monkeys: Age differences in learning.	0
First report of reindeer (Rangifer tarandus tarandus) response to human-given cues.	0
Effect of resource-associated signals on producer responses: Insights from golden fish (Carassius auratus) and an agent-based model.	0
Computerized intertemporal choice task in chimpanzees (Pan troglodytes) with/without postreward delay.	0
Incorporating animal agency into research design could improve behavioral and neuroscience research.	0
Putting the best foot forward: Limb lateralization in the Goffin’s cockatoo (Cacatua goffiniana).	0
Supplemental Material for Pitch Affects Human (Homo sapiens) Perception of Emotional Arousal From Diverse Animal Calls	0
Do standard behavioral assays predict foraging behavior of individual Black-capped chickadees (Poecile atricapillus) in response to a predator model or calls?	0
Food calls enhance visual discrimination learning in chimpanzees (Pan troglodytes verus).	0
Supplemental Material for Exclusion by Donkey’s Ears: Donkeys (Equus asinus) Use Acoustic Information to Find Hidden Food in a Two-Way Object-Choice Task	0
The impact of training method on odor learning and generalization in dogs (Canis lupus familiaris).	0
Supplemental Material for Personality Structure in Wild Eastern Chimpanzees (Pan troglodytes schweinfurthii)	0
Exploring personality structure and similarity in coppery titi monkeys (Plecturocebus cupreus).	0
Supplemental Material for Recognition of Visual Kinship Signals in Chimpanzees (Pan troglodytes) by Humans (Homo sapiens)	0
Supplemental Material for Spatial Frequency and Global–Local Visual Processing in Capuchin Monkeys (Sapajus spp.) and Humans (Homo sapiens)	0
What is simple is actually quite complex: A critical note on terminology in the domain of language and communication.	0
Supplemental Material for Primate Socio-Ecology Shapes the Evolution of Distinctive Facial Repertoires	0
Correction to Burghardt (2021).	0
The dynamics of chunking in humans (Homo sapiens) and Guinea baboons (Papio papio).	0
Rules and metarules: Adult cotton-top tamarins (Saguinus oedipus) and 5-year-old children (Homo sapiens) can master both.	0
Dominance in human (Homo sapiens) personality space and in hominoid phylogeny.	0
100 years of comparative psychology advancing practice, policy, and the public—And what the future requires.	0
Visual and acoustic exploratory behaviors toward novel stimuli in Antillean manatees (Trichechus manatus manatus) under human care.	0
Supplemental Material for Vocal Repertoire and Auditory Sensitivity of White-Throated Woodrats (Neotoma albigula)	0
Forgetting curve in spider monkeys (Ateles geoffroyi): Effects of delay but not the amount of information.	0
Are chimpanzees futurists? Effects of motion lines and motion blur on the judgments of global motion direction in chimpanzees (Pan troglodytes).	0
Factors in forgetting in spider monkeys, Ateles geoffroyi.	0
Should I stay or should I go? Pigeons’ (Columba livia) performance of a foraging task has implications for optimal foraging theory and serial pattern learning.	0
Supplemental Material for Are You as Fooled as I am? Visual Illusions in Human (Homo) and Nonhuman (Sapajus, Gorilla, Pan, Pongo) Primate Species	0
Supplemental Material for Putting the Best Foot Forward: Limb Lateralization in the Goffin’s Cockatoo (Cacatua goffiniana)	0
Editorial.	0
Supplemental Material for Monkeys (Macaca mulatta) Rank Lists Using Multiple Cognitive Mechanisms Simultaneously	0
Supplemental Material for Still Face in Pet Dogs (Canis familiaris)	0
Supplemental Material for Form Over Function: Striped Skunks (Mephitis mephitis) Learn Arbitrary Visual Patterns to Solve the Slat-Pulling Task	0
Using isochrony, but not meter, to discriminate rhythmic sequences in rats (Rattus norvegicus).	0
Supplemental Material for Guatemalan Beaded Lizards (Helodermatidae: Heloderma charlesbogerti) Navigate and Follow a Scent Trail in Maze Tasks	0
Search asymmetries for threatening faces in chimpanzees (Pan troglodytes).	0
A modified version of the dimensional change card sort task tests cognitive flexibility in children (Homo sapiens) and cotton-top tamarins (Saguinus oedipus).	0
No same–different concept or entropy stimulus control: Multiple-item array task performance in budgerigars (Melopsittacus undulatus) and pigeons (Columba livia).	0
Supplemental Material for Humans’ (Homo sapiens), Capuchin Monkeys’ (Sapajus [Cebus] apella), and Rhesus Macaques’ (Macaca mulatta) Size Judgments Shift When Stimuli Change in Frequency	0
Decision-making by bushveld gerbils (Gerbilliscus leucogaster).	0
Reach-to-grasp kinematic signatures in Colombian spider monkeys (Ateles fusciceps rufiventris).	0
Assessing cats’ (Felis catus) sensitivity to human pointing gestures.	0
Vocal repertoire and auditory sensitivity of white-throated woodrats (Neotoma albigula).	0
Is economic risk proneness in young children (Homo sapiens) driven by exploratory behavior? A comparison with capuchin monkeys (Sapajus apella).	0
Evaluation of decision-making behavior under uncertainty in capuchin monkeys (Sapajus apella) and humans (Homo sapiens) using a modified Balloon Analogue Risk Task.	0
Looking back to look forward: Avenues into the field of comparative psychology.	0
Delayed gratification: A grey parrot (Psittacus erithacus) will wait for more tokens.	0
Hearing “number”? Relative quantity judgments through the echolocation by bottlenose dolphins (Tursiops truncatus).	0
Do that again! Memory for self-performed actions in dogs (Canis familiaris).	0
Target number influences strategy use by rats (Rattus norvegicus) in the traveling salesperson problem.	0
Preference or flexibility? Spatial navigation by Syrian hamsters (Mesocricetus auratus) in a multiple-cue environment.	0
Detouring while foraging up a tree: What bull ants (Myrmecia midas) learn and their reactions to novel sensory cues.	0
Changes in temporal cues elicit rhythmic discrimination in rats (Rattus norvegicus).	0
Supplemental Material for Conflict Interference in an Insect	0
Supplemental Material for Changes in Temporal Cues Elicit Rhythmic Discrimination in Rats (Rattus norvegicus)	0